Electric kiln.



6 1718 Z4 J6' am W J. L. HARPER W. J. LARKWORTHY. ELECTRIC KILN. v APPLIUATIO FILED 00T. 7, 1907. BENEWD MAY 18, 1909.

925,902. I Y Patented June 22,1909. A v ZSHEBTE-SEEBT 2.

UNITED sT-ATEs -PATENT oEEroE.

' JOHN LYELL HARPER AND WILLIAM JOHN LARKl/VORTHY, OF NIAGARA FALLS, NEW YORK;

SAID L ARKWORTHY ASSIGNOR lO SAID HARPER.

4ELECTRIC Application led October 7, 1907, Serial No. 396,236. Renewed Hay 18, 1909.

. ing glass, and similar pur oses. The kiln is constructed to .conserve e ectrical energy by transferring heat from the outgoing finished product to the incoming raw material. In its preferred construction, the kiln comprises a longitudinal series of chambers, having parallel tracks on which trains of trucks carrying the articles to be heatedare moved in opposite directions. The sourceof heat is located in the middle chamber and the temperatures of the other chambers progressively decreasetoWa-rd both ends of the kiln. The severalchambers and the tr'lcks are referably of equal length, and when the kil) operation each chamber is occupied by two adjacent trucks of the oppositely-moving trains.- yThe trains are moved simultaneously at intervals, so that the trucks of each are vsuccessively shifted, first from chamber to chamber of increasing temperature, up to the heating chamber, and then through chambers of. decreasing temperature, until they leave the kiln. The periods between the shifting of the trucks are suiiicient to permit the transfer of heat from the articles 'on each truck leaving the source of heat to those on the other truck in the same chamber, until the temperature of the two becomes substantially equal, so that when the finished articles leave 4the kiln their temperature is but little above that of the atmosphere. The trucks have end walls which close the openings in the partitions between the adacent chainbers, retarding the longitudina flow of heat through the chambers, and the kiln-walls and the doors and end `walls of the trucks have dead-air spaces .to retard the flow of hea-t therethrough. The preferred heatmg means is a series of carbon resistors, extend-v ing transversely across the top of the middle chamber.

Referring to the accompan` 'in drawings: Figure l is a vertical longitudinz section of the heating chamber and portions of two Specification oi Letters Patent.

n is inA Patented Jun@ 22, racc. serial No. 496,718.

heat-equalizing chambers of 'a kiln, on the line I-I of Figs. 2, 3, 4; Fig. 2 is a horizontal' longitudinal section of the same chambers on the line II-II of Fig. 1 Fig. 3 ,is a vertical transverse section of the heating chamber, on

the line III-III of Fig. 1 Fig. 4 is a vertical i transverse section of a heat-equalizing chamber, on the line IV-IV of Fig. 1 and Fig. 5 is a vertical longitudinal section of a ortion of the roof of a heating chamber aving modified resistors.

- In the specific construction illustrated, theheating chamber l has an arched roof 2 and side-walls 3 Athe inner faces 4 of which are inclined to assist in' reflecting heat onto articles on the trucks. Each of the heat equalizing chambers 5 has an arched roof 2', in line with the roof 2 of the heating chamber, and vertical side-Walls 3, set inward from the side walls 3 of the heating chamber. The

'inner faces 6 of the walls 3 are vertical.

The roofs 2, 2 and side walls 3, 3 may be built of common brick lined with fire-brick,

and contain dead-air spaces 7 for heat insulation. The space 8 above the roofsmay be iilled with sand or other poor conductor of heat. Thev adjacent chambers of the kiln are partially separated by two spaced transverse walls 9, each containing two rectangular openings 10 to receive the end walls of the trucks. The lower portion of each chamber is divided by a longitudinal Wall 11, to sepl'arate the trucks ofl the two trains.

.hrough the chambers 1, 5 run two parallel lines of tracks 12, each carrying a train of trucks v13. Each truck has a floor 14 and end walls 15 of refractory tile containing dead-air spaces. The trucks are of the same length as the chambers 1, 5, and their rectangular end walls 15 are of such size as to substantiallyfill but not touch. the edges of the openings 10 in the transverse partitions 9. The spaces 7' between the endwalls contain non-circulating air and communicate with the dead-air spaces 7. Horizontal ribs 3, 11, projecting from the side Walls 3, 3 and the intermediate wall 11 of .the kiln, extend loosely into horizontal grooves 14 in each side of the truck-floors 14, and retard the escape of the heated air.

The heating means illustrated comprises a longitudinals'eries of transverse continuous resistors 16, each preferably consisting of a Wide thin bar or granular element 17 of carsurrounded by a refractory sheath 18, for example of y These resisters are rvedlo'ngitudinally in the arc of' a circle bon orlgij'aphite,

l andlare looselyg-mounted in separate openingsgfilfin .tha-'refractory lining-arch 'of the 'root The terminal endsv 17 ofthe resister'- barsfare'fyrelatively thickand extend out of zthe sides of 'the' heating lo f to the electric mains 22.

.the graphite terminals .are bare an n chamber between clamping-,plates 20, 21, which are connected The up er sides of the upper clam mg plates 20 preferably oi graphite, it

1 21, any-resister may be.slidlongitudinallyK l close yfnponthem,l providing' a joint oflow c resistance. 'Byun amping the plat'es120,

out of its opening into a pitat 'the lside Ifor repair orrenewal.

in the modification magnate-in rig-f5',

the roofoi the heating chamber has transwer slots 23.- Each a carbon orgraph'ite sheath 1 8, mounted in verse recesses 19 `with resister 16 comprises bar 17 and'reiractory a refractory non-conducting support 24.

y i source vof heat-energy,

` the recesses 19' eiiectively insulated, or bein This support has an upper such shape and size as to loosely enter one oi and slots 23 ,in the roof, being removable withits contained resister. This kiln enables articles to be uniformly heated to a high tem 'consumption o energy, little of the heat being lost 'through the walls,

which maybe carried away by the outgoing product. hile the kiln 1s especially 'designed to employ'electricityv as a the center chamber may be provided with grates for coal or I thirteen chambers and by the use of resisters saggers for burners for liquid or gaseous fuel, in lieu :of the resistors, if a high temperatureis-not required. The kiln may conveniently have as a heating means the heating chamber may be maintained at a temperature of 3,000F., the iirst set of heat-equalizing chambers at each end of the heating chamber, at 2,4000,

the second set at1,800, the third set at 1,200",

strai ht line.

I c aim: i

1. A kiln, consisting of a tunnel divided into a longitudinal series of chambers, means for heating anA intermediate chamber, and two trains of trucks movable in o posite di- Krections through the tunnel, eac chamber receiving two trucks land permitting the unrestricted low oi heat between the Acontents of said trucks.

iianged rib 24 of erature with the. minimum b kiln, the several close the openings in said 2. A kiln, consisting of a tunnel divided into alongitudinal series of chambers, means for' heatingan intermediate chamber, two trains of trucks movable in opposite directions through the tunnel, the several and Y chambers and trucksbeing ci substantially thesame length. A 3. A kiln, comprising a longitudinal series vof chambers, transverseaperturedpartitions A means forfheating an intermediate chaber, and .two trains of trucks movable oppositev directions through the kiln, the several chambers and between. said chambers,

trucks being of substantially thesame length and the trucks being constructed to substantially close ,titi'onszV r- 4. A kiln, comprising a longitudinalserics of chambers, transverse apertured parti'- tions between the chambers, means for heating an termediate chamber, and two the openings said partrains oftrucks movable in opposite direc-H tions;V through the kiln, the several chambers and trucks being of substantially'the same I length, and the trucks having heatinsulat-A ing floors and end-walls, said end-walls substantially closing tions.

into a longitudin for electrically heating an intermediate chamber, and two trains oi trucks movable 5. A Consisting of a runner-divided al series of chambers,imeansthe openingsl in said partiv in opposite directions throughthe tunnel,

`each chamber receiving two trucks and permitting the unrestricted iiow of'heat between the contents ci said trucks. v v

6.'. A kiln, consisting of a tunnel divided into a longitudinal series of chambers, elec-V tric resisters in position to heat an intermediate chamber, and two trains of trucks'movable in opposite directions through the tunnel, each chamber receiving two tru'cks and permitting the unrestricted llowA oi heat between the contents of said trucks.

7. Alkiln, consisting-of a tunnel divided into alongitudmal'senes of chambers, electricresistere carried. by the roof of an in-tei'- mediate chamber, and two trains of trucks movable in op osite directions through the tunnel,each c amber receiving two trucks icc and permitting the unrestricted flow of heat between .the contents .of said trucks.

8. A kiln, comprising a longitudinal series o f chambers, transverse apertured partitions between sald'chambers, electric resisters carried by the roof of anrintermediate chamber,A and two trains of trucks movable in Vopposite directions through the chambers and trucks being the same length and the to substantially artitions.

of substantially trucks being constructed 9. A kiln, comprising a o f chambers, vtransverse apertured partitions between said chambers,longitudinallyongitudinai Series removable electric resistors cerried by the In testimony whereof, we affix our signaroof of an intermediate chamber, and two tures in-presence of two witnesses.

trains of trucks movable 1n opposite dlrections throu h the kiln, the several chambers 1 C JOHN ELL HARPER'- 5 and truoksgbeing of substantially the same l WILHAM JOHN LARKWORTHY length and the trucks being 'constructed to Witnessesz'I substantially close the openings in said par- FRANK E. REID, titions. l

v BENJ. F. LEE. 

